module ActiveRecord
  module ConnectionAdapters
    module MySQL
      class SchemaCreation < AbstractAdapter::SchemaCreation
        delegate :add_sql_comment!, to: :@conn
        private :add_sql_comment!

        private

          def visit_DropForeignKey(name)
            "DROP FOREIGN KEY #{name}"
          end

          def visit_ColumnDefinition(o)
            o.sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale, o.unsigned)
            super
          end

          def visit_AddColumnDefinition(o)
            add_column_position!(super, column_options(o.column))
          end

          def visit_ChangeColumnDefinition(o)
            change_column_sql = "CHANGE #{quote_column_name(o.name)} #{accept(o.column)}"
            add_column_position!(change_column_sql, column_options(o.column))
          end

          def add_table_options!(create_sql, options)
            add_sql_comment!(super, options[:comment])
          end

          def column_options(o)
            column_options = super
            column_options[:charset] = o.charset
            column_options
          end

          def add_column_options!(sql, options)
            if charset = options[:charset]
              sql << " CHARACTER SET #{charset}"
            end

            if collation = options[:collation]
              sql << " COLLATE #{collation}"
            end

            add_sql_comment!(super, options[:comment])
          end

          def add_column_position!(sql, options)
            if options[:first]
              sql << " FIRST"
            elsif options[:after]
              sql << " AFTER #{quote_column_name(options[:after])}"
            end

            sql
          end

          def index_in_create(table_name, column_name, options)
            index_name, index_type, index_columns, _, _, index_using, comment = @conn.add_index_options(table_name, column_name, options)
            add_sql_comment!("#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})", comment)
          end
      end
    end
  end
end
